| Calfreezy Holdings Limited | Information & communication | 2015 |
| Calicem Limited | Information & communication | 2023 |
| Calinga Limited | Health & social care | 2022 |
| Call Centre Consultancy Services Limited | Professional & scientific | 2020 |
| Callapitta Ltd | Information & communication | 2015 |
| Callatech Precision Engineers Limited | Administrative & support | 2003 |
| Callaways Limited | Construction | 2000 |
| Callenmuir Homes Limited | Hospitality | 2018 |
| Calleya Limited | Real estate | 2022 |
| Callisto Agency Systems Co. Limited | Information & communication | 2017 |
| Cameo Coins Ltd | Wholesale & retail | 2021 |
| Cameron Stuart Associates Limited | Administrative & support | 2015 |
| Camilla's Design Limited | Professional & scientific | 2010 |
| Campanilla Limited | Hospitality | 2014 |
| Campbell & Glasby Ltd | Other services | 2013 |
| Campbells Parts Ltd | Wholesale & retail | 2024 |
| Candela Consulting Limited | Professional & scientific | 2003 |
| Candour Diamond Limited | Manufacturing | 2020 |
| Candytuft Gifts Limited | Information & communication | 2025 |
| Capeij Limited | Wholesale & retail | 2020 |
| Capital Aerials LLP | | 2012 |
| Capital Cleaning Services Limited | Extraterritorial | 2014 |
| Capital Clouds Web Ltd | Wholesale & retail | 2024 |
| Capital Hygiene Limited | Administrative & support | 1985 |
| Capital Plumping Labour Ltd | Administrative & support | 2026 |
| Capital Steel Structures Limited | Construction | 2007 |
| Capitaz Ltd | Manufacturing | 1994 |
| Cappc Consult LLP | | 2016 |
| Capranet Consulting Limited | Professional & scientific | 2020 |
| Captcha Ltd | Extraterritorial | 2010 |
| Cara Counselling Training Ltd | Other services | 2022 |
| Carbon 1.5(UK) Limited | Professional & scientific | 2024 |
| Carbon Capture Testing Ltd | Professional & scientific | 2024 |
| Cardean Estates Limited | Administrative & support | 1993 |
| Cardinal Court (Worthing) Limited | Households | 1980 |
| Care Active Limited | Education | 2007 |
| Care and Clear Solutions Ltd | Construction | 2026 |
| Care Delivery Limited | Construction | 2015 |
| Care Providers Limited | Professional & scientific | 1994 |
| Care Vista Ltd | Health & social care | 2026 |
| Caremark International Limited | Health & social care | 2007 |
| Caremark Limited | Health & social care | 2005 |
| Carers Support West Sussex | Other services | 2007 |
| Carlile Plumbing & Heating Limited | Construction | 2012 |
| Carlton Hardware Limited | Wholesale & retail | 2018 |
| Carlyon Ventures Ltd | Other services | 2016 |
| Carmen Calvo Ltd | Professional & scientific | 2021 |
| Carnegie Gardens Management Company Limited | Households | 1989 |
| Caroline Beashel Limited | Administrative & support | 2013 |
| Caroline Keylock Consultancy Limited | Professional & scientific | 2013 |
| Carousel Tattoo Limited | Other services | 2015 |
| Carpenter Box Limited | Professional & scientific | 1989 |
| Carpol Insurance Consultants Limited | Financial services | 1977 |
| Carre Expansion Limited | Professional & scientific | 2002 |
| Carre Plus Limited | Professional & scientific | 2002 |
| Carre Rouge Ltd | Professional & scientific | 2012 |
| Carringwood Limited | Construction | 1992 |
| Carringwood Properties Limited | Construction | 2013 |
| Carry on Crafting Ltd | Administrative & support | 2021 |
| Cartech (Autocentres) Limited | Wholesale & retail | 1997 |
| Cartotrade Limited | Information & communication | 2014 |
| Cartouche Ltd | Construction | 2021 |
| Carty Building Contractors Ltd. | Construction | 1997 |
| Carty Holdings Limited | Professional & scientific | 2009 |
| Carty Properties Limited | Real estate | 2012 |
| Casanovas Barbers Limited | Professional & scientific | 2010 |
| Casavesta Ltd | Real estate | 2023 |
| Cascade Learning Limited | Education | 2011 |
| Casco Europe Limited | Manufacturing | 1997 |
| Cash Control Limited | Wholesale & retail | 1980 |
| Caspar Henderson Ltd | Wholesale & retail | 2014 |
| Castle Accommodation Ltd | Real estate | 2019 |
| Castle Agentiq Ltd | Information & communication | 2025 |
| Castle Goring Limited | Real estate | 2012 |
| Castle Horizon Ltd | Financial services | 2025 |
| Castle Lodge Developments Limited | Real estate | 2006 |
| Castle Management Solutions Ltd | Professional & scientific | 2017 |
| Castle Move Consulting (CMC) Limited | Professional & scientific | 2025 |
| Castle Residential Lettings Limited | Real estate | 2011 |
| Castle Support Homes Limited | Health & social care | 2024 |
| Castle Walk Reigate Limited | Extraterritorial | 2008 |
| Castleview Homes & Developments Limited | Real estate | 2025 |
| Castleview Storage Ltd | Other services | 2018 |
| Castor & Pollux Limited | Arts & recreation | 2007 |
| Catalina Echo Limited | Financial services | 2010 |
| Catalina Finance LLP | | 2023 |
| Catalina Holdings UK Limited | Financial services | 1999 |
| Catalina Services UK Limited | Administrative & support | 1945 |
| Catalina Worthing Insurance Limited | Financial services | 2006 |
| Catastrofx Pedals Ltd | Wholesale & retail | 2025 |
| CATCH44 Consulting Limited | Professional & scientific | 2024 |
| CATCH44 Technologies Limited | Professional & scientific | 2025 |
| Catergas Limited | Manufacturing | 2015 |
| Catfish Media Limited | Information & communication | 2019 |
| Cathedral Investments Limited | Real estate | 2025 |
| Catherinearolt Ltd | Education | 2023 |
| Catrisse & Co Limited | Wholesale & retail | 2026 |
| Causeway Management Co. Limited(The) | Households | 1963 |
| Cavendish Mews (Worthing) Management Limited | Households | 2000 |
| Cavitech UK Ltd | Construction | 2013 |